Pore-scale origins for nonequilibrium subsurface flow: Preferential pathways, rate-dependency, and hysteresis
Ran leads the Engineering Applications of Fluid Mechanics group within Fluid and Complex Systems Research Centre. His interest is fundamental understanding of environmental and energy applications in which multiphase and reactive subsurface flow is key.
Of particular interest is the pore-scale origins of nonequilibrium— emergence of unstable, preferential pathways, hysteresis and rate-dependency, and their interplay with hydrodynamics, phase transitions and matrix alteration due to bio-chemo-mechanical processes such as fracturing and dissolution. His research cuts across the interface of earth sciences, engineering and physics, combining experiments, numerics and theory. Ran received his PhD from UC Berkeley. He was a postdoc in MIT, an assistant professor in the Hebrew University (Israel), and a visiting scholar in the Institute of Environmental Assessment and Water Research (IDAEA-CSIC) in Barcelona, Spain.
Multiphase and reactive fluid flow in soils and rocks is often unstable, and highly heterogeneous: inevitable microstructural heterogeneity leads to the emergence of preferential pathways, where most of the flow is focused in a small portion of the medium. Furthermore, strong hysteresis and rate-dependency are frequently observed. This complex behaviour is further corroborated by interactions between the fluids and the solid matrix, e.g. fracturing and dissolution.
I will overview several examples of nonequilibrium flows, including fingering instability and hysteresis in multiphase flow associated with heterogeneity and wettability effects, as well as geomechanical and geochemical processes. I expose the underlying mechanisms by a combination of simulations, experiments, and theory, and discuss implications for soil moisture, migration of contaminant and hydrocarbon, and carbon geosequestration.